A container terminal is a facility where containers are loaded to or unloaded from ships and containers are carried in and out by external chassis for overland transport. The container terminal also is a facility where the containers unloaded or carried in are temporarily stored.
Nowadays, along with rapid evolution of container transport systems in international traffic routes, cargo handling and storing works in container terminals have been required to achieve further automation and energy saving. More specifically, what are important are automation, efficiency enhancement, cost reduction and the like in operations of transporting containers between ships and a container terminal and storing containers in the container terminal.
To address this, there is a container terminal including: storage lanes extended in a direction substantially perpendicular to a quay; an automated guided vehicle configured to switch direction between the storage lanes; and an area which has a gate placed on the opposite side from the quay side, and in which a external chassis and a transfer crane (yard crane) perform cargo handling (for example, see Patent Document 1). This container terminal is capable of increasing a storage area ratio and achieving further automation of the container terminal because external chassis, i.e., the external chassis attended by operators do not enter the storage region.
However, this container terminal has a problem of a poor cargo handling efficiency, in particular, in operations of carrying a container stored in the storage lane out to the external chassis and carrying a container in from the external chassis and storing it in the storage lane, since the yard crane moves over the storage lane while holding containers. This is because the moving speed of the yard crane is approximately 18 km/h, which is quite low.
Meanwhile, in the container terminal described in Patent Document 1 still requires the moving distance of each transfer crane (yard crane) to be increased to place containers in arrangement enabling efficient loading onto the ship or carrying-out to the external chassis. In the case where a storage lane is provided to extend in a direction perpendicular to the traveling direction of the quay cranes, in other words, in the land-and-sea direction, the cargo handling efficiency is enhanced if containers carried in from external chassis and being to be loaded on ships are placed on the seaside of the storage lane while containers unloaded from ships and being to be carried out to external chassis are placed on the landside of the storage lane. The container terminal described in Patent Document 1 has an efficiency reduction particularly in carrying containers out to and in from the external chassis because the yard crane travels over the storage lane while hoisting up the containers.
Moreover, the method in which a yard crane hoists and transports containers is poor in cargo handling efficiency, and therefore has a problem of wasteful energy consumption.
Meanwhile, there is a container terminal which is provided with yard cranes configured to move in a longitudinal direction of a storage lane, and is designed to dividedly store containers to be carried out and containers carried in. This container terminal includes a yard crane 111 straddling a storage lane 110, and a large yard crane 112 straddling the yard crane 111 as illustrated in FIG. 14. Since the yard crane 111 and the yard crane 112 can pass each other without collision, this container terminal can store containers k in the storage lane 110 in efficient arrangement. However, the container terminal still has to move the yard cranes 111 and 112 for long distances, and requires a longer time accordingly. In addition, there also arises a problem that the manufacturing cost and maintenance cost for the large-scale yard crane 112 are high.